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BIOL 2301 Human Anatomy & Physiology I - BIOL2301_lecture09_0921
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00:03 Morning. See if I do it way. It doesn't help, does
00:13 ? Yeah. All right. So , what we're doing is we are
00:25 up with the epithelium, uh or in, we're gonna just look at
00:29 nails and glands and then what we're do is we're gonna jump into ose
00:34 , which um kind of serves as baseline of the background to understand the
00:39 themselves. So our starting point is nail. This is more a more
00:46 less a let me just memorize the are sure to get one on the
00:49 . That's about it. Um There a theme though that if you've been
00:54 attention, you notice that in the when we've talked about the epithelium there
00:57 when we talk about the epidermis, was an underlying layer on which
01:02 When we looked at the hair, had a matrix which had all the
01:05 cells and that's where all the cells from. And the same thing is
01:09 on here in the nails, we an underlying tissue from which nails
01:14 Now, I'm gonna start there even the list is not there.
01:18 So the starting place is here in nail matrix. Your nail matrix sits
01:23 down deep. All right. And about which way your nail grows.
01:28 it grow this way or does it that way? If the, if
01:31 pointing, does it grow upward or it grow outward? Goes outward?
01:35 right. So you can see what doing is from the nail matrix.
01:39 are producing the bed on which it and from which that plate is growing
01:47 . So when you think of a , the thing you're looking at is
01:49 plate underlying the plate is the If you want to make this
01:53 if you ripped your nail off, would look at the bed. All
01:57 , the plate is the hard part . Now, in and of
02:03 that's, that's basically all you need know about a nail. Why do
02:06 have nails? Well, it helps to grip and grasp on to
02:10 Um It also helps to protect the of your fingers if you've ever,
02:14 you're like me and you bite your because reasons um if you've ever bitten
02:19 too low or if you've trimmed your too low, you know how it
02:23 a lot, right? It's because is a very, very sensitive area
02:27 us to understand what it is that grabbing and gripping. All right.
02:32 it's there to help protect that underlying . The, the very tips of
02:37 fingers. Now, there's some other I just want to point out just
02:40 , uh, if you've ever wondered that white part is, it's called
02:43 nu. All right. Um, cuticle is not the things on the
02:48 . The cuticle is the portion It's a little layer of skin that
02:53 the matrix. So it's the part down here and it's also called the
03:00 . Um, I don't have it here, but if you ever want
03:02 know the area underneath the nail, , is called the Hypo Nicki.
03:06 if you saw, um, uh, uh, put, put
03:11 boots, did you see that some you, do you remember when he
03:15 the Spanish, uh the Spanish splinter the Spanish toothpick? I can't remember
03:19 you call it when he stuck the into the Yeah, right in the
03:24 . So that's not a lot of if you ever jabbed it in
03:27 Something in there. Not a lot fun. All right. So that
03:30 the nail. And then what we're do is moving on to the
03:36 Uh There are two different types of associated with the skin and we're going
03:40 start with the one that we all , which is a sebaceous gland.
03:43 the reason we hate it is because around the age of 12 to
03:47 all of a sudden you woke up big volcanoes on your face. All
03:51 . And these are a function of type of glands, the sebaceous
03:54 all right. They produce an oily . This substance is called sebum.
03:58 can see here in our little there is a sebaceous gland, there
04:03 a hair follicle. The sebaceous gland typically associated with that. All
04:08 the sea bum is important for you what it does is it kills things
04:14 the surface of your body, It's bacterial cyle in nature, meaning
04:20 contains within it proteins that kill off . So it's a protective barrier.
04:26 also contains in it RN A and Aces. So it also serves as
04:30 first line defense against other microorganisms, like a virus. All right.
04:35 what I want you to do is want you to think about it being
04:37 . So what do we do every with ac we wash it off,
04:42 we? Yeah. So what? so we washed and all the other
04:50 that stink. But in the we're also clearing away the layer that
04:53 protects us. So this is natural of protection. So you have to
04:58 kind of choose which is better stinking you know, soap also kills
05:04 So that's why it works. All . Now, the other thing,
05:08 , first off, it's a holocrine glance or remember holocrine, what type
05:12 secretions it's producing, right? It's oil stuff. It's the cell rupturing
05:19 releasing that, that goo, that cell made into the pores and what
05:24 does is in these hair follicles. it's coating and softening hair. So
05:29 find pictures on the internet. So is one of the reasons why you
05:31 post pictures of yourself on the don't make them available because I just
05:36 the oily student and this is what get. Yeah. Yeah. And
05:43 just terrible. I mean, that was my search term,
05:47 I don't know whose student they but you can see I was
05:49 there's oily hair, you can see on the face. And so what
05:53 doing is we're putting this oily substance the surface of our skin to protect
05:58 also in our hair to soften it and also to protect the hair cells
06:02 it has a lot of fats in . It also helps to prevent excessive
06:07 loss, but mostly it's there as . All right, moving from
06:12 we're gonna go off to the second of gland when we think of
06:16 This is what we think of when think of glands. This is typically
06:19 we think of as the p Sudi . And there are two types,
06:22 is called the meri or eg the one is a sweat gland. Notice
06:28 we covered all three different types of structures in this little thing here.
06:34 right. So here you can see where they're located, we have an
06:39 that's associated with hair follicles. Notice is different than the sebaceous gland.
06:43 right, here, we can see meri gland. It opens up directly
06:46 the surface of the skin. these are everywhere on your body.
06:51 two exceptions. First, is the . Why the nipple? Well,
06:54 nipple is an actual sweat gland. right. So when we think of
06:59 and we think of lactation, this a function of a type of gland
07:04 has been modified for a different purpose mammals. All right, we move
07:08 from there. You won't talk about again until reproduction because it makes you
07:13 uncomfortable, doesn't it? Ok. . All right. The other type
07:19 . Well, that's a whole another of wax. So anyway, start
07:26 the ari sweat glance. All Now, arin sweat gland is when
07:30 think about sweating, we typically think sweating underneath our arms. All
07:34 And that's not true. I no notice when you were walking over
07:38 in the, what is it? degree heat right now? At 8
07:40 in the morning? I mean, you notice that you're sweating all over
07:43 body? Did you notice that? ? Ok. So notice that when
07:49 think about sweating, we normally think our pits, but really, our
07:52 body plays a role in sweating. Arquin sweat glands are weird because they're
07:58 in two specific areas. In the as well as in the anogenital
08:03 So basically in your crotch. All . Now, these are basically emptying
08:10 into the hair follicles and it kind makes sense. Think about what you
08:13 underneath your under, in your right? You have hair follicles and
08:18 it's doing is secreting this thicker material these structures. Now, what the
08:24 is that it's producing is not just , but it has fats and it
08:29 proteins in it and the fats and proteins are very attractive to bacteria who
08:35 like to live in warm wet right? Which would be the pet
08:38 in the crotch. And what they is they now have a food source
08:42 they can consume and in doing their byproducts of consumption is this stinky
08:47 that we then call body odor kind weird. Huh? Your body odor
08:52 really your odor. It's the stuff lives on you odor. So if
08:55 says you stink, say no, , no. It's the bacteria on
09:00 . I don't, I don't know that's better. So, all
09:03 Anyway, so why do we have ? Well, we don't really
09:09 All right, you, whenever you at something, the question you ask
09:12 is, does it have a Does it serve its purpose? Does
09:16 in our pits and in our crotch us down because that is one of
09:20 primary purposes of sweat is thermodynamic or regulation. And the answer is
09:25 it really doesn't. But the interesting is these types of glands do not
09:30 particularly active until at puberty or All right. So, I have
09:36 boys who are 12 years old. is in the midst of puberty.
09:39 hasn't started yet. One stinks to heaven. The other one does not
09:45 . He still stinks. He smells a wet dog because that's what a
09:48 boys smell like. They smell like dogs. You didn't know that.
09:52 wait. Yeah. And then you to puberty and then they stink worse
09:57 a wet dog. And guys can to this. Right? We,
10:01 know right. But what happens is now we're sweating through with these
10:08 and it's presumed these may actually serve a sexual scent gland, right?
10:14 most other mammals, uh, tell , the opposite sex that they are
10:20 mature through sexual scent glands. I , typically if they do so,
10:25 they are uh estrus type animals, do. So at specific times of
10:30 . So you, if you have cat or a dog, you know
10:32 they go into heat at a specific of year. And part of the
10:35 that the other sect knows that they in the, producing a scent that
10:40 animal actually recognizes humans do not have sexual cycle. We do not live
10:46 cats and dogs and only are capable producing once a very small portion of
10:51 of the year, we're able to sex whenever we want to and
10:55 Whenever we want to give a small window of MS menstruation. And through
10:59 menstrual cycle, we're not gonna go all that stuff. But the point
11:02 , is it, this may be way that we kind of tell the
11:07 sex that we're old enough to be successful. All right. Now,
11:13 , I'm not walking up to you saying, hey, smell my
11:17 See, I'm, that's not the . But the, it's, it
11:20 in the category of all the different that kind of demonstrate sexual maturity.
11:26 the belief right now for this. it makes sense given where it's
11:32 the other type of gland. the one that we most think about
11:35 we think about sweat is the Merin the ri sweat gland. Who's
11:40 You wanna know does commercials? he's a, he's a professor at
11:46 University of Texas in the Thank Matthew mcconaughey. I can't believe he's
11:51 professor, please. And I can't . It might be Menendez. Maybe
11:58 JLO. I don't know, it's of them. I don't know.
12:04 , she's an actress, right? pick people that you should be able
12:08 recognize, but I'm old and I recognize young actors anymore. Actually,
12:12 reason I picked him is so he's he grew up in Uvalde Texas.
12:16 wife is from Uvalde. My brother-in-law him sound exactly alike. If I
12:21 . It's the weirdest thing. It's a Uvalde accent. It is the
12:25 you hear him. And it's anyway, so what do we have
12:29 ? These are everywhere, especially on palms of your head, uh,
12:33 of your hand soles of your Forehead. Think of all the places
12:36 are sweaty all the time. All , these are there and they cover
12:41 entire body. All right, what is the thing that they produced through
12:46 glands is basically filtrate of the And that's pretty much true about any
12:50 of watery thing that your body It's material that's taken from the
12:55 Water is primarily other stuff. Sweat water plus a couple of other
13:00 So it doesn't have all the proteins the fats, but it does have
13:03 materials in it. Its function is simple, thermoregulation. Let's keep the
13:09 temperature down in that range that makes functionally viable. So what happens
13:14 is your body produces sweat, which water that sits on the surface.
13:19 open up blood vessels that bring water the surface heat is transferred from
13:24 the blood to the water on the . When those water molecules get to
13:28 right temperature, right? They basically off your body and move away and
13:33 the heat with it, how your cools itself. All right, in
13:37 , it doesn't work so well because already have a lot of water in
13:41 air. So it takes a lot effort for water to be wicked away
13:44 your body. All right. I up in El Paso. It's dry
13:49 . Sweat is wonderful because it cools down all the time. All
13:54 The other things that you're going to here is that it excretes materials from
13:58 body, things, your body doesn't when we typically think of it.
14:01 um excretion, we think of, basically urination and we think of
14:07 We also think maybe even in respiration you're expiring air. But this is
14:12 way to get things off your particularly nitrogenous waste is one of the
14:18 that leaches along with the water outward gets on the surface. So it
14:23 a metabolic role as well. And , it plays a protective role.
14:28 we've already talked about sebum being This is also protective, it has
14:33 in there. Um There's uh different of immunoglobulins uh that you'll hear this
14:38 over and over again. If you've heard of Iggigaigcigdig at the beginning is
14:45 immunoglobulin. These are the proteins that responsible for protecting you from foreign
14:52 All right, from foreign particles. your way that your immune system identifies
14:59 . And one of the things that secreted out is igaig A is specifically
15:05 on the surface of the body and binds up foreign things so that they're
15:08 big to actually move in the body they can be recognized by immunocyte to
15:14 it. One of the chemicals that releases is called dermoid and it even
15:19 it, dermis skin side and kill an antibacterial. So, one of
15:24 things that we do is we kill pathogens on the surface of our skin
15:29 that they can't work their way All right. Now, the thing
15:34 Marrin sweat glands is that they're uh, sympathetically regulated. And what
15:38 means is is that they are gonna when you need to do a couple
15:43 things. Basically, it's when you to cool yourself down. All
15:47 So, um, there are things when you're exercising, so sympathetic deals
15:53 the three es ex exercise energy or , it's um, excitation, you
16:00 kind of emergency another one. excitation emergency. So, if you're
16:05 to give a talk, right? you're nervous about it, you
16:09 you start sweating, right? Why you sweating? Because that nervousness is
16:15 being excited and it's an emergency situation you just want to escape. And
16:20 part of that escape mechanism is I to cool the body down as I'm
16:24 blood through my body. That would the, the example. All
16:28 So this type of sweat just isn't for fun. It requires sympathetic activity
16:35 do. So is what we're looking . So does he do that?
16:38 this kind of make sense to understand difference between the oil on your
16:43 the gross pit sweat and then the sweat, the irregular sweat. We're
16:50 with that. OK. Ready to into the other tissue. No
16:57 You're not, not ready. I'm gonna do it anyway.
17:01 sometimes you just have to barrel All right. So really what today's
17:09 is about is gonna be about I really wish I could figure out
17:14 to bring that down for you guys that's really bad. Yeah. Um
17:22 we're primarily going to be talking about , but I need you to understand
17:26 when we're gonna be going through the system that the bones are just a
17:31 of the skeletal system. We have things in there like cartilage, which
17:34 don't spend a lot of, a of time talking about, we'll have
17:37 like ligaments and there's other types of tissues that are associated with bones
17:43 Cells to allow the skeletal system to it and to allow muscles, to
17:48 the things they do along with the system. But really if we cover
17:54 bones, we're kind of good That's, that's kind of the good
17:57 approach here. All right. So are bones? Well, they are
18:01 primary organs. They are an So when we look at the
18:05 each bone is an individual organ, work independently of each other and then
18:09 work collectively together to do particular All right, they provide a framework
18:17 which your body is derived. All . In other words, you are
18:21 , the way you're shaped and you the way you look because your bones
18:25 that, that look. All And there's a functionality to that as
18:30 . Now, if you look at bone, you'll find that some of
18:33 bones have a cavity and that cavity a connective tissue, which we're going
18:37 describe a little bit later called And this marrow can either be red
18:42 yellow depending upon your age and depending where it's located. And that marrow
18:48 an important role, not in supporting bone, but actually in creating
18:53 All right. So the cells of blood come from marrow, which is
18:57 weird. So it's a system when talk about the skeletal system that isn't
19:03 about protection or providing framework, it allows for an environment to produce a
19:10 different connective tissue. Um It is tissue is the name we talked about
19:17 here. Oh, and there are types of bones. So when we're
19:20 at a bone, I want you be keeping your eye open. For
19:24 two different characteristics. We have one that is called compact bone. All
19:29 . When we think about bone, is what we think of. It's
19:31 it's dense. It, there's, no whole or anything like that.
19:35 usually on the outside. It makes because of its density. It makes
19:40 about 80% of the mass of a , right? So when you pick
19:43 a bone and you look at you're probably looking at compact bone.
19:47 if you break a bone open and on the inside, you're going to
19:50 a different type of bone, It's called spongy bone. Other texts
19:55 actually give you a word like cancel or Trabi, Trabi Trabi or Trabi
20:02 to strands. So it looks more a sponge. Hence the term spongy
20:07 . All right. And here it's , very porous and we'll see examples
20:11 this in the moment and because of porousness, it actually doesn't have a
20:16 of money, but it does have lot of strength. The so we're
20:24 bone, the dense stuff. I see spongy bone whenever we look at
20:28 bones. But it's their their arrangements kind of become important. So the
20:36 thing we kind of need to do kind of need to know what's going
20:40 , on the inside and on the of a boat. All right.
20:43 what we have is we have a of connective tissue on either side.
20:49 , we're gonna be focusing here on long bone. All right. But
20:54 gonna use this to help us visualize on the outside All right. So
21:01 the inside and on the outside of cells, we are of the
21:04 we have a specialized connective tissue that made up of the cells of uh
21:11 are that, that build bone as as the fibers that are uh connective
21:17 that serve as a protective barrier. , on the outside, there's more
21:22 and there's uh and so what we here is we see this, this
21:26 covering that's found on the surface. so you can see here, this
21:29 an example of a flat bone. so you can see this would be
21:33 top on the outside, this is the bottom, on the outside.
21:36 so you have this layer of tissue has these little tires and fibers that
21:42 into the bone itself and then nearest bone is where we're going to find
21:47 layer of cells. So this is dense, irregular connective tissue. All
21:53 . And if you've ever eaten you ever eaten ribs. All
21:56 And you get down to close to rib, you can actually grab this
22:00 your teeth and you'll feel it peel sometimes and you don't want to eat
22:03 and you just throw it aside right . If you're eating, you
22:07 pork ribs, the meat just falls the bone. But if you're eating
22:11 nice old beef rib, you oh yeah, you'll feel this stuff
22:15 you'll get down there just pulling on . It's like connect you just
22:18 oh, it's just a connective It is connective tissue but it's not
22:22 the muscle, it's of the You can tear that meat away because
22:26 one of the ways that it is . Now, the cells that we're
22:29 see here that are closest to it the ones that are building the bone
22:33 it. There's three different types of . We're going to see osteopro
22:37 osteoblasts, and then we're going to some osteoclast as well. And we'll
22:41 to what those cells are in just bit. The harder one to visualize
22:46 there's not a good picture of it what is making up the endosteum.
22:50 right. So this right here is medullary cavity of a long bone.
22:54 , it's a hollow space inside the bone inside there. That's where you're
22:59 see spongy bone. And on the of that spongy bone, you don't
23:03 the same type of connective tissue What it is is mostly just a
23:07 of cells wandering around building and breaking bone. All right. So you
23:13 mostly the cells, you lack a tissue. Now here inside this uh
23:21 bone, you will see the same of endosteum, but it's not as
23:25 as you would if you have a giant cavity where you can look at
23:28 surface. All right. So the here is if you can think about
23:32 like this. If I have a that is hollow on the outside,
23:36 have periosteum on the inside, I endosteum. All right on the outer
23:43 is a connective tissue of fibers and inside between the hard bone and
23:49 that layer of tissue are the layer cells. And then when I'm dealing
23:52 the endosteum, it's just a bunch cells running around. OK? They're
23:56 floating around, they're on the surface the bone. Ok? Now we're
24:01 get in close and we're gonna hopefully at this and see it a little
24:04 better. But I want to start because it, it puts this
24:09 in uh in uh kind of working . The other thing I'd point out
24:13 you can see in this little you can see there are blood
24:16 All right. I wanna remind you are organs. So that means they
24:20 consisting of living tissue. All they're very much alive, even though
24:24 think a bone is not being it's very much alive. So you
24:27 to provide nutrients. So what the does, it allows you to bring
24:32 structures close and hold them into place allows the blood vessels to penetrate the
24:37 to penetrate. Now, we start the long bone because it's the most
24:44 bone and then everything else kind of from that. All right. And
24:48 I want you to do here is first that we're looking at external
24:54 right? So, if we're pulling bone in our hands, we're
24:57 we're naming what we see on the , the long portion here. All
25:03 , is called the shaft or the . All right. The diaphysis,
25:09 you cut it open has a very hollow space, that's that medullary
25:14 Remember what we said when you see word mela, it means middle.
25:18 medullary cavity means in the middle, giant gaping space. All right.
25:22 the medullary cavity is typically filled with when you're a child, that marrow
25:27 gonna be red marrow. And when become an adult, that red marrow
25:30 replaced and is replaced by yellow which is predominantly fat, which should
25:36 you feel real good about yourself, is another place to put fat in
25:39 body. Yeah. All right. we move to the ends, the
25:47 of the bone is called the All right. So epi means on
25:52 the end or above. So the sits um on the opposite ends of
25:59 diathesis. All right. Now, you look here in the cartoon,
26:02 you cut it open, what do see? You don't see a big
26:06 medullary cavity. Instead, it's filled spongy bone. So what we have
26:10 on the outside, whether you're looking the diaphysis or the epithets, the
26:14 is always always, always this compact and then as you move inward,
26:18 replaced with this Trabi bone or spongy . But when you look at
26:24 you have a big hollow space. you look at epithets, you have
26:28 but spongy bone. All right. then we have a really weird region
26:33 is not shown in the picture, it really is found right around
26:38 OK. So if you look through cut, you can see I have
26:42 region of compact bone, then it spongy bone and then it's this strange
26:48 of bone that is a type of bone before I get to the spongy
26:53 again. And so it's the region this, that's uh called the
27:00 Now, this region contains this little piece of compact bone is called the
27:06 growth plate. All right. And you can see the name is referring
27:09 the epithets. This is what allows to grow in the vertical direction.
27:16 when you were little, think about tiny you were right? And then
27:19 grow and your limbs grow and your grow. Well, I should say
27:23 legs and your limbs are the same , your arm and your legs
27:26 And what you're doing is you're adding length a uh in this direction.
27:31 the reason you're able to do that because that region of the epithet or
27:36 , the epis growth plate is not , it's cartilage. And what you're
27:40 is you're laying down cartilage and pushing epithets away from the diaphysis and the
27:46 is growing to try to catch up the epithets and that's why you get
27:51 and tall. We'll get to that more detail at the end of the
27:55 . In theory, I may end talking for seven minutes about a
27:58 That's totally unnecessary. Right? I do. Come on. All
28:07 So when you look at all the bones, right? So if the
28:10 bone is the one with the hollow , all the other bones in your
28:13 don't have hollow cavities. Instead, still have the compact bone on either
28:18 and on the inside, we have spongy bone and we give it a
28:21 name because why not give you one thing to memorize, right? It's
28:25 diplo. All right. So when see the spongy bone inside uh a
28:31 that's not a long bone. We to it as diplo and again,
28:36 space is going to be filled with . I should have backed out this
28:40 in here. This spongy bone is to be filled with marrow. All
28:45 . It's the cavity in the lung that is also filled with marrow.
28:50 right. No ma cavity. That's key thing to take away from
29:00 Now, there are different types of in your body. Again, what
29:03 like to do as scientists, we to take things we like to see
29:06 matches the other things. We like throw things into the boxes and label
29:09 and say this is what it All right. And so what we're
29:13 is we're of doing this in terms shape. We're gonna look at
29:16 we look at bones and we say type of shape is this. And
29:19 we really kind of break it down three types and then what ends up
29:23 is is that we keep creating these that can be crossed over between different
29:28 of them. So the first one just want to just kind of mention
29:31 is the flat bone, which is we saw in this kind of picture
29:34 here. The flat bones characteristically are be flat. All right. So
29:41 that means is, is they have very, very thin um appearance,
29:46 ? They have compact bone, they some spongy bone and compact bone and
29:50 elongate in one way or another. not long wi like we saw in
29:55 long bone, they just are flat , all right. Now, here's
30:00 weird one. So some of these gonna make sense. They're well,
30:03 terms of their functionality, they lie some sort of soft tissue and and
30:11 there to prevent things from getting to soft tissue? So the easy ones
30:16 can think about are like the cranial of the skull. I mean,
30:19 your helmet Right. So that's Long and flat. We got a
30:22 of those. Right. You might of your sternum. All right.
30:26 protects my heart. So this is flat bone. It just sits right
30:29 the middle of my chest. One we have a hard time thinking
30:34 look at a rib. It looks it's long and it's true. It
30:37 long. But if you put it its side, you'll see that it
30:41 flat curved surface like the other bones it doesn't have the cavity, which
30:46 characteristic of the long bones. So we hold it and look at
30:50 what does it have to fall It falls into the long bone
30:54 right? We'll see in a That's the shoulder blade. All
31:02 Now, I'm pointing this out now it's just a weird thing and you'll
31:08 them, but we never really talk them beyond one bone, which is
31:11 patella, which is the bone that your knee. That's your knee
31:15 Yes, sir. Correct. The bones do not have medullary cavity.
31:22 only bone that has med cavity is long bone. All right, everyone
31:29 are all boring except for their I think that word comes from
31:38 which is sesame seed. It's I'm glad no one said sesame.
31:45 possible. You never know. All . If you think about a sesame
31:48 , sesame seed has a particular If you ever ordered a big
31:51 You seen a sesame seed? All . Little tiny, like oblong shape
31:56 they're all over your body. they're these small, little flat,
32:01 , they're tiny. They don't, so small. They don't earn
32:04 All right. There's one exception, is the patella, which is technically
32:08 seso bone. But sometimes we throw in a different category or, or
32:14 in a different category which we're gonna here in just a minute. All
32:17 , we're gonna call this a, short bow. But when you see
32:21 , I'll point them out when we're at like, let's look, there's
32:24 button and it has no name. right. But they exist and there's
32:28 of them. The other three the ones that are important are,
32:33 we've mentioned are the long bones. then we have the two others which
32:35 gonna be the short and the All right, a long bone,
32:40 are longer than they are wide. have the medullary cavity. Typically,
32:44 you're gonna see is they will have shaft, the Diapy, those two
32:49 , they are the shape when you of a bone. This is probably
32:52 you think about and you're gonna find primarily in the upper and lower
32:57 All right. And when I say this is so this is a long
33:01 , the only on the radius, bone, long bones that make up
33:05 heart. They make your fingers, make up your toes. I'm
33:14 not the axis, the appendicular the legs and the arms. Almost
33:19 in there is a long bone. exceptions. We point out the
33:24 Get there. All right, short , they are roughly the same length
33:30 they are in width. So they of have a square I appearance notice
33:35 , they're not exactly squared. The I have up here is gonna be
33:41 patella. We have the carpal bones the tarsal bones. Those are the
33:45 that make up your wrists and they up your ankles. All right.
33:50 you'll see when we look at Yeah, they're kind of cuish.
33:53 look kind of like dice. All . They're not exactly, but they're
33:57 of like, all right now, I have seso bodes here. What
34:02 seso bones? They are these weird . So some people categorize them as
34:06 bones. And then the last group like, OK, I pick up
34:10 bone. I look at it. not a long bone, it's not
34:12 short bone. It certainly isn't I don't know what to do with
34:16 . We'll throw it in the other . That's the irregular bones. All
34:19 . So your vertebrate are irregular the bones, uh there are several
34:24 of the face that are uh these of bones, the bones that make
34:29 your hips, the Os Coxa, three bones that fuse during development become
34:34 bones and then those two bones connect each other and those are your hip
34:39 . That's the osa. They are regular bones. They don't have a
34:44 that makes sense with the other three . All right. So if the
34:50 doesn't make sense, throw it in irregular box. Now, it's really
35:01 if you take anatomy classes from, , people who are classically trained in
35:08 , they want to spend eight days about all these things, right.
35:13 , they spend more time on the and the muscles than they, than
35:16 necessary. If you're planning on going a career of health care, the
35:20 who deal with bones and muscles as therapists, right? And they really
35:26 of deal mostly with movement. So less about the bones and the
35:29 more about, are you capable of the movement that's necessary? Right.
35:34 , it's, it's, it's kind a shift nurses. They don't need
35:38 lot of knowledge about bones. I , need to know what they are
35:42 what they do and what their purpose . But do you need to know
35:46 marking? Every thank you. That's answer I'm coming up with too.
35:50 , when I think about when so yesterday I went to the doctor's
35:53 , I got, had to go blood the, the, uh,
35:57 , you know, comes up to , starts slapping my wrist. What
36:01 you do? Well, I'm a . What do you teach?
36:03 I teach biology. I teach anatomy physiology and she says, oh,
36:06 great. And then we started talking stuff but she didn't know anything about
36:10 . All she has to do is where the vein is. Stick
36:14 pull my blood, send me on way. Didn't even give me a
36:17 band aid. I was really upset that. I asked. Right.
36:27 what you'll find when you move from class is that you will find people
36:32 are going to want you to spend lot of time learning this and there
36:35 a nomenclature and a language that goes understanding bones. And so what I
36:41 to do is I want to introduce to one of the ways that we
36:45 . I or how we identify bones , and really kind of their functions
36:49 their purposes. All right. So are what are called the bone
36:54 So if you pick up a bone the lab, how are you guys
36:56 the A and P lab right All right. You guys doing bones
37:00 ? Yeah. Are you guys touching feeling these things? Yeah. And
37:04 part of this is to understand, just which bone I'm looking at,
37:08 what is its job? All So one of the types of bone
37:12 you'll come across is what is called depression. And there are different types
37:16 depressions. And you can see the names over here, we have facets
37:19 fossas and phobia and grooves. And purpose is really to do one of
37:24 things. Basically, it makes sure the two, when they meet each
37:28 , there is something that allows them articulate together to either hold them together
37:33 to create movement between the two All right. Or another thing is
37:38 what it will do is it provides point that would be a good example
37:42 a groove, a point where a or a nerve travels along the surface
37:46 a structure. So it creates a special pathway for these structures.
37:52 when you're looking at these bones and see a depression, the question,
37:55 should be asking, what is this for? All right, why did
37:59 give it this particular name? we do this for a whole bunch
38:03 different things, openings. These are holes in the bones. So
38:08 if you see this word meat. right, that's how it's pronounced.
38:13 when we talk about the ear, going to learn about the ear
38:17 That is the auditory me. All . Um You have fissures, which
38:22 gonna see uh when we look at , the brains or the,
38:27 the cranium itself or you'll see for is plural is gonna be for,
38:33 which just seems really weird because uh a seems like baby for a but
38:38 not so like at the base of skull is the Framan Magnus, the
38:43 giant gaping hole through which your spinal travels down. All right. And
38:48 do you think? Frame? And means if Freeman means hole, what
38:52 you think? Frame? And Magnus the big hole? So all of
38:57 sudden now it's like, what do mean? They're, they're not this
39:01 . No. If somebody look at , oh that's the big hole,
39:04 the big hole and from there move your, you know, right or
39:08 . Yeah. No, you don't . These are just examples,
39:13 The idea here is what is its ? Why are there openings? We
39:17 saw depressions? Why are there Right? Why do they exist?
39:23 ? Part of the reason? All . So to answer your question,
39:25 real question you're asking is, so something I have to memorize here in
39:29 of the pictures in terms of the . And the answer is no.
39:33 ? Because I'm not handing you a and saying, identify this depression.
39:38 don't go over the bones like In this class. There's 100 of
39:42 . We can't pass bones around and everyone touch them. This is why
39:45 have labs. All right. So what we're doing is we're learning the
39:49 and its purpose. All right, purpose of the structure. All
39:54 So things allow things to pass from side of the bone to the
39:58 All right. Think about your Right, right here. That's the
40:04 fissure. Your eye is connected to brain via the optic nerve. If
40:10 was no fissure, no optic nerve be going to your brain if that
40:15 sense. All right. So blood vessels nerves travel through bones as
40:21 . Then we have projections. there's a whole bunch of different
40:24 You'll hear con dials, you cress heads, tubercles tubes at this
40:29 . I think they're just making up to make it confusing. I don't
40:32 the word tubercle. I will use . I don't know. Again,
40:37 are just historical epic Conal. How that different than a Conal? It
40:42 above a con dial. So it will make sense if you
40:46 if this is a con the thing above it that protrudes outward would be
40:51 all right. And again, what these? These are points where muscles
40:55 a tendon or a ligament is gonna to the bone? So it sits
40:59 away from the bone for that particular . There's others. So like the
41:08 or the, the can, there's clever one, the protuberances, you
41:14 why your head doesn't fall forward because have the protuberances. You can actually
41:19 it on the back of your It sits right there, feel that
41:23 right there and there is a muscle attached to that. That's what allows
41:27 to do this plus all the bones the neck that allow you to rotate
41:33 that axis. All right spines When you see these words, what
41:39 we doing? There's something attached, what we just need to understand.
41:50 the takeaway from this is understand the of a depression, understand the function
41:56 a process, understand the function of opening. All right, it's there
42:03 a reason and then when you look a bone, it's like, oh
42:07 pointing out this structure here for a , right? So if, if
42:14 studying the humerus and you see the tuberosity, you guys know what a
42:20 toit is the shoulder muscle, So what is the purpose of the
42:25 tuberosity? What do you think to the deltoid muscle? And then what
42:31 I do? I could do the dance because of it doesn't have to
42:38 the chicken dance. All right. here's marrow, what we've done.
42:43 do you think this structure is right ? It is, it's a,
42:48 this is a slice through the diaphysis through the metaphysis so that you can
42:54 into an ESIs, right? So is looking inward to the epithets.
42:59 you can see out here, here's compact bone and then all in
43:03 there's your spongy bone. All And what we're looking at is this
43:09 inside the spongy bone. So remember I said, the spongy bone contains
43:13 it marrow. It's found within this of trabecule. There are two different
43:20 we have red marrow. Red marrow called word to try to spell.
43:27 that should be the test. Learn to spell Amata. Poetic.
43:31 it's Yeah. When you get to iepoeiy, yeah. Nightmarish.
43:39 So poetic literally means a tissue that responsible for producing blood cells.
43:46 So poetic referring to it making cell poetic would be making red blood in
43:58 blood cells, blood cells. All . So when you're looking at red
44:05 , that's what it does in we're gonna find it in the bones
44:09 our, in the. We'll also it in our flat bones. So
44:16 you are owner as an adult, got to go to some pretty horrific
44:21 to try to find an arrow no the tops of these bones which are
44:29 easy to get to. Not a of fun. All right. So
44:33 is why a dope is a big . You should just like applaud them
44:37 you're like a dough because you first to go digging with a big giant
44:42 and then you go drilling. It's like for oil right now.
44:48 Children are different. They have red basically everywhere, right? So they
44:54 only have it up here. They have it in their medullary cavity.
44:58 the reason for that is they're producing and tons of red blood cells to
45:03 and allow them to grow and to off all the horrible things that life
45:07 throwing at them. All right. what happens is is as you age
45:13 red marrow will become replaced by the marrow. So you can kind of
45:17 this again. This is the right? And you can see in
45:20 there's kind of this yellowish fatty looking , but it's still surrounded by red
45:25 . And so here what's happened is that the body is taking the red
45:29 and saying, well, we don't as much red blood cell production as
45:33 normally when we did as a So we're gonna ramp down and lose
45:38 of those stem cells that are sitting producing space gets filled up by a
45:45 competition, the output. Now in event that in dire need of red
45:52 cells, what will happen is is there will be a signal that causes
45:56 stem cells to start replicating themselves so you have a bigger pool of stem
46:00 so that you can make more red cells. But that's like emergency.
46:04 when like we got to do All right. So when you become
46:10 , very, very anemic anemic just you're not producing red blood cells.
46:16 right now, most of y'all have yellow marrow than you did four years
46:22 . All right, for me, mostly fat. So that doesn't surprise
46:29 . So far does this stuff make ? It's pretty straightforward, pretty
46:32 Right. I hope. All Ok. Good. It,
46:35 I don't want it to feel like is like nightmarishly hard because sometimes what
46:39 do is we like to put up barriers and say, oh, this
46:41 too hard for me to learn. right. Like calculus. It's too
46:45 for me to learn. So we want to do it. What we're
46:49 now is we want to shift. we say, OK, well,
46:51 this is a tissue and each of bones are an organ, there must
46:55 cells that make up this tissue and this organ to be an organ.
47:01 so that's kind of where we're Next is we're looking at the four
47:04 bone cell types. All right. this little graph here shows you the
47:09 cells we have osteoclasts. All The general thing that you can walk
47:14 with this is that these, their of osteoclast is to break down.
47:19 right, the other group. So other three are related to each
47:25 We have a stem cell that is an osteogenic cell. It produces or
47:30 not produces, it divides and differentiates an osteoblast. The osteoblasts job is
47:37 make bone tissue. And then once uh cell matures, it becomes an
47:44 . Its job is to maintain the . So we have three or,
47:49 really four jobs here, I'm I'm stem cell that differentiates becomes the
47:56 which then ultimately becomes the maintainer. you go through this progression of maturation
48:02 then the ostin class is unrelated to first three or the or the second
48:06 , they stand aside on their And so this kind of is more
48:11 AAA more descriptive of these just looking the osteogenic cells. So what we're
48:17 at here is we're looking at the of bone tissue. All right.
48:24 this is really in the meine back bone is even formed. And what
48:29 can see is they're starting to become organization. So cells are going to
48:34 and become these osteogenic cells. So you hear the word osteogenic, that
48:39 they are stuck down the bone that's the direction they have to
48:43 And they're, they're found within the tissue that they are making. And
48:48 ends up happening is they differentiate, leave behind cells that then differentiate into
48:57 . So the osteogenic cells are in connective tissue, they're being pushed away
49:01 the tissue that they're going to be . And so underneath, when they
49:05 , they leave behind become the And we remember what we said whenever
49:09 see blasts at the end of the name, it means it's not its
49:13 phase. I guess you can say , you go through different stages,
49:18 or somewhere in the middle. All . So the osteogenic cells are dividing
49:24 they're moving away from the tissue. right. But they can't move far
49:29 they're stuck in other connective tissue. down the connect the, laying down
49:35 bone is the osteoblasts and they're not bone down in one direction, they're
49:42 laying down matrix in all directions. so while they're doing that, you
49:47 imagine if you're painting in a room you can paint in all directions,
49:51 you're doing is you're painting yourself into circle, right? And now you
49:55 stuck with all the paint around stuck the matrix that you built. And
50:02 what you see here. This cell been stuck. I'm still making
50:08 The osteoblasts are building matrix and building around and that some of them get
50:13 . And now I have my mature . It differentiates and becomes an
50:18 This is very much a living And you can see that this cell
50:23 inside the bone. It built, actually has extensions and those extensions that
50:28 artist didn't show goes out and touches osteo cells. So the other sites
50:35 well as osteoblasts, you can see there are little canals within that
50:40 So there that flows around the cell provides the nutrients and the materials.
50:46 then those cells are actually detecting the integrity of that matrix to determine whether
50:51 not it's strong enough to do the it's supposed to do. So when
50:57 talk about maintaining the matrix. We're those cells to judge and determine whether
51:03 not your bones are strong enough to the activity that you regularly do.
51:10 kind of kind of cool. So you sit around on the sofa all
51:14 and just watch tiktok, how strong bones gonna be? You're not gonna
51:19 very strong. Why? Because your not gonna waste energy to keep a
51:23 matrix. But your mom takes your away from you, throws it against
51:27 wall, says get out of the and now you have to walk to
51:31 friend's house to go watch tiktok. what's gonna happen to your bones?
51:35 gonna get stronger as a function of stresses that you're putting on your
51:42 Exercise is good for us because it our bones to strengthen themselves dependent upon
51:49 type of activity we do. That's of cool. Our bones shape themselves
51:55 do the activities. We do a aside. One of my younger
52:02 uh, was at school one I think I already told you
52:04 Um, and they were running around gym because reasons and someone did that
52:11 thing. You know, when you the other person's foot out from underneath
52:14 , you know, tripped him and put it out on his arm to
52:17 himself, landed on it, broke his own, on the rap.
52:20 was awful. I went to go him up. They said your son
52:22 his arm and I said, come over, his arm was a
52:25 , right? Because the bones had both broke, one actually penetrated through
52:29 skin, you know, it was , and surprisingly, he wasn't
52:33 he was that much in shock. was just like, you know,
52:36 we took him in to do you know, to the hospital and
52:39 reset the bones and if they can within, I think it's 15 degrees
52:44 the normal shape, then they'll send on your way with the cast.
52:48 if they can't, then they have go in and pin it and stuff
52:51 they are able to set it so it was within 15 degrees. So
52:55 arm looked like I can't walk this . That was kind of how it
53:00 when he, when, when they it, right. But it
53:03 it was in this direction right now came off and that's what his arm
53:09 like because it was set like Right? And then he started doing
53:13 normal activity. What does his arm like now? Normal? Right.
53:19 the bone reshapes itself to do the that needs to be done. It's
53:24 of the osteoblast and the osteocyte and osteoclast that allow that to happen.
53:31 . What do osteoclast do? osteoclast break down bone. It is
53:37 , really cool. I think I'm have this on the next slide.
53:39 in essence, what it does is your bone is there, it's a
53:44 that not only plays a role in , it also plays a, as
53:49 as a, as a reservoir for and phosphate. And so when your
53:53 needs calcium and phosphate, it can that from the bone kind of a
53:58 resort. But what happens is as using your bones and as you're exercising
54:02 you're moving around and stuff like the body detects the stresses those osteocyte
54:07 it tells the osteoclast what it can down and what it needs to leave
54:12 . And so your body is constantly and, and breaking down bone over
54:18 course of your lifespan. And in , it's incredibly active. Now,
54:23 you see here is you can see little cartoon is trying to show you
54:26 like, oh here's an osteoclast and digging a hole in the bone and
54:30 is on the surface and this is typical. But you'll also see this
54:34 you're talking about sponges, sponge So here you can see spongy
54:38 right? And I love this picture it's, if you know Pacman,
54:42 we have inky, pinky and uh Blinky and pinky. No, no
54:47 knows Pa Pacman. There's no I don't know why Clyde's not up
54:52 , but apparently they're being chased by Pac Man. Anyway. So you
54:55 see here what, what, what we done, we have broken down
54:59 bone. So this would be here's normal bone, we're detecting this
55:03 is not a useful bone. So happens is the osteoclast comes along and
55:09 the bone. All right. So destroys bone releases calcium releases phosphate,
55:15 maybe it overdid it. So what's now? Or maybe this, we're
55:19 that this is an area where there's high degree of stress. So osteoblasts
55:22 rolling in and they rebuild or reform bone and that matrix. So here
55:29 we're doing is releasing calcium and remodeling bone based on stress needs. And
55:35 again, we're remodeling based building bone on those stress needs. And then
55:40 body just does this all the time give you a sense. You basically
55:45 5 to 7% of your bone mass week. That means over 20
55:50 years. How long? 52 So, unless and twice you do
55:56 twice a year, you basically remodel whole body in terms of bone
56:00 you don't rebuild your entire skeleton. . But the idea is like,
56:05 there this is not dead tissue. is very much a live tissue remodeling
56:09 , dealing with the stresses and the of your musculoskeletal system. So that
56:15 creates the strongest you that you need be. All right now, compact
56:25 is replaced much, much slower than bone. Why do you suppose that
56:30 exactly, it's a density. It's what we're saying, it's thicker,
56:34 harder, so it's much harder to . So this matrix, what are
56:40 looking at? All right. What this weird looking thing that we're
56:47 Well, if you start down here the end, we're, this is
56:51 of going in the direction of how get to that bone itself. And
56:57 you look at bone, we'd say consists of both an organic and an
57:02 component. Now, the inorganic is simple. It's calcium and phosphate come
57:08 . These are crystals that are then on the organic components of the
57:14 And these are what are formed with other elements are called hydroxy appetite
57:19 So the reason bone is hard is it has its calcium phosphate in it
57:28 makes up the majority two thirds roughly the matrix. But if you look
57:33 the matrix itself, we have this that's called osteoid asteroid is the collagen
57:38 the arrangement of that collagen. And we're gonna find within that asteroid.
57:43 gonna see cells, the cells are to create the osteoid. The asteroid
57:49 these collagen fibers. So here we a collagen fiber at the molecular
57:53 we take three of them wrapping we get this strong helix, you
57:58 a bunch of these helices, you them together and you've got something that's
58:01 stronger. And then you throw crystals it that gives it its hard and
58:05 you wrap those in the bundles and you've got this massive stiff collagen fiber
58:10 been os ossified and then you take and then you arrange them in particular
58:17 . And now you have the structures which bone is actually built. And
58:23 we're gonna be creating is a structure called an osteon. The osteon is
58:29 thousands upon thousands of these fibros which derived from these long lengthy collagen
58:39 Do you ever go watch the The side? OK. I know
58:43 reason I mentioned the blind side is of at the beginning of the blind
58:47 , they show a game of the and the giants. All right,
58:53 Lawrence Taylor and Joe Theismann, whose name is Joe Theisman, but they
58:59 marketing campaign when he was in they changed it to Theismann to sound
59:05 Heisman, right? So yes, all right. I was, you
59:12 interrupt the story. So the idea , is that uh this is a
59:20 and twisting strength. This is why see the story, why it becomes
59:23 here in just a moment, whereas actually gives it rigidity. So think
59:27 this right here. My nose Why is it bone? What is
59:36 ? It's cartilage, right? This , I can stretch it and bend
59:40 stuff. So there's strength to but there's flexibility. All right.
59:45 when you put in the, the , what it's gonna do is,
59:48 gonna be inflexible back to the So the story of, of the
59:57 side, the reason they show this the beginning of the movie is because
60:00 want to show you the importance of defensive tackle or an offensive tackle on
60:03 blind side. So Lawrence Taylor was phenomenal linebacker. He ate quarterbacks for
60:10 . He was big, sweet but he's big and mean on the
60:14 field. And so he came on blind side, Joe Theismann was rolling
60:18 on a play, a play action . Lawrence Taylor is faster,
60:24 caught up to him, grabbed him the legs and did what a good
60:28 was supposed to do to the ground make him the Theisman fall to the
60:35 and hit the ground, right. you just try to tackle him,
60:38 can step out of ST Lawrence Taylor what he's supposed to do and immediately
60:43 he tackled him, Lawrence Taylor jumps , looking at the sidelines, starts
60:47 . Get here, get here, here real quick. He knew what
60:50 happened. He had heard it he had taken that bone in the
60:54 portion of the leg and had twisted by a, he basically, he
60:59 planted the foot and when he he had taken and to,
61:03 create a torsion to cause the bone splinter in this direction. That was
61:09 end of Joe Theismann's career right Again, it wasn't Lawrence Taylor's
61:14 It was just bad luck. He exactly what a linebacker was supposed to
61:18 , but it took a man of strength to be able to do
61:23 Bone does not twist. It It's not supposed to twist and it's
61:27 twist because of this arrangement. All , there are lots of things in
61:32 body that can twist, cartilage twists fine has flexibility. Bone does not
61:36 flexibility. All right, it's there be strong to hold things and
61:43 it's arrangement is what gives it its and its ability to resist torsion.
61:51 let's take a look and see what is. Now. If you haven't
61:58 the blind side, it's a great story. It's actually not, it's
62:01 untrue I think. But about Michael um what we have here is a
62:08 through the diaphysis. So you can up here, here's my bone,
62:12 ? You can see there's the medullary . This is a compact bone over
62:18 on the edge, right on the of that medullary cavity. That would
62:21 where we find the spongy bone. out here, what have I peeled
62:25 ? What's that called? Do you periosteum? So line here, that
62:29 be where the endosteum would be OK. So your frame of reference
62:34 important here because you're gonna see something looks repetitive over and over again.
62:40 we're gonna be looking at is this here this osteon. All right.
62:45 so that's what's been cut out. you can kind of see this has
62:48 hollow center, doesn't it just like have this hollow space, this medullary
62:53 ? So there's this hollow space inside osteon. And if you look at
62:57 osteon up here, the cartoon, if you look carefully, you'll see
63:00 black dots create these boundaries between So it's basically a series of rings
63:06 a bunch of bull's eyes. Those represent the osteoid laid down by the
63:14 as they were building this uh ring . OK. The little black dots
63:21 here represent the osteocyte trapped in this . So when we look at a
63:30 bone, what we're looking at really a whole bunch of these jammed up
63:34 each other. So you can see are all osteon, right? And
63:40 we have all these pillars that are and strong, they're basically bunched up
63:43 . It's like getting a bunch of and wrapping them with hundreds and hundreds
63:47 band aids and then taking those and trying to break them, right?
63:52 why we have strength and why when try to grip those, those pencils
63:57 we could actually grab onto them how force we'd have to use to and
64:00 break them this torsion. Now, other thing I'd point out here is
64:05 at the direction of the line. what we've done in this little picture
64:09 is we've pulled one osteon out. . So we've kind of pulled out
64:13 see the different layers. And you see in one layer that the lines
64:18 this way and then the other the lines go that way and then
64:21 way and then that way and what have here is a weaving pattern.
64:26 in essence, what we've done, have fibers that resist twisting in one
64:31 , fibers that resist twisting in the direction and you build them over and
64:35 again. And so now we we this mesh work that doesn't want to
64:38 at all and then again, wrap with other ones. And now you
64:42 something that's really tough. This is bone is tough. All right.
64:46 they resist to torsional stress, they compression stress, right? Just tough
64:55 . Now, these osteon are gonna the length of the diaphysis. All
64:59 . This is why the compact bone is so dense. Now,
65:07 when you look inside an osteon, is what we would refer to as
65:11 the functional unit of a bone. right. So whenever you hear
65:14 it's like if I broke it broke it down, what makes a
65:17 strong? It would be the So what makes up the osteon?
65:22 oops, that's that functional unit. so what we said is remember we
65:25 this kind of space and then we ring ring and then you got these
65:29 of rings that hollow space is called central canal. And inside the central
65:34 , you have blood vessels, you'll a vein and you'll have an artery
65:37 we're not gonna cover a P one carry blood to tissues. Blood,
65:41 veins carry blood away from tissues. . The better definition is arteries carry
65:47 from the heart. Veins carry blood the heart. But for your
65:51 artery to the tissue vein, away the tissue is fine. You'll also
65:56 in their nerve fibers that are located that central canal. So you can
66:02 pain. You can, you can signals to the nervous system about things
66:07 are going on inside the bone. see each ring of fiber, those
66:14 called the concentric Lamela. All So concentric meaning they're just rings that
66:21 repetitive. They have the same ring that central canal. So this is
66:25 is actually and I mentioned already the is going in opposite directions. So
66:29 is what gives the strength and the to the bone itself. And
66:33 as we mentioned already, we have osteocyte that are trapped between the
66:39 They're the ones that were the osteoblasts laid down the Lamela and then got
66:43 in it. And so they're there uh maintaining the matrix, making sure
66:49 matrix is doing what it's supposed to doing in our little cartoon. You
66:53 see that they have these extensions, the space and with within which,
66:58 within that um osteo um state lids called a Lacuna. When you hear
67:04 word, what does it sound like you? Sounds like not, I
67:11 about to go there. But if had to translate that into English without
67:14 your Latin, what do you think sounds like lagoon or like, I
67:22 , either of those people Lacuna maybe lake. All right. So basically
67:29 a space surround filled with fluid where is. And you can see.
67:34 these are electron micrograph showing you And so you can see how it's
67:39 hollowed space. And so that's where find the cells living and there's little
67:46 canals in between each of the different . So you can kind of see
67:50 in this one. They're, they're shown here uh through which these little
67:57 are being extended. And so these baby canals are what they do is
68:03 allow cells to actually communicate with other in that network or in that,
68:09 that tissue. And so you get pattern, central canal concentric with the
68:17 where you have the osteocyte and you get a series of those rings.
68:27 , in order to get an artery into that central canal, there has
68:30 be a place where that blood vessel in and moves out of that
68:35 And so we have perforating canals this is a terrible picture and I'm
68:40 show you why because osteon are move , the the length of the long
68:47 . All right. So they, are as long as the long bone
68:49 . And this kind of suggests that , that this is a two
68:53 So basically, it's only this long that's not true. It's just this
68:57 portion right here is basically a hole goes through it. So it perforates
69:02 the osteon. So think of a trunk and then dig in a hole
69:06 the tree trunk that would be a . And then you take a bunch
69:12 these when we said, remember if get a whole bunch of,
69:15 of uh pencils and I wrap them rubber bands, what I'm basically doing
69:19 using something to hold all those things . So we have Lali that are
69:25 like the rubber bands and so you see them on the outside. So
69:29 have uh a series of lamel that going around the entire circumference and we
69:35 them on the inside as well. the one on the outside is called
69:39 external circumferential lamel. And the one the side is the internal circumferential
69:45 And so what we're doing is basically , oh, as I'm building the
69:49 , I've got the shape of the bone. And so I'm laying down
69:53 or, or this, this osteoid the outside and basically it's just getting
69:58 and bigger and bigger and it's being down. Remember what we said on
70:02 outside, what do we have periosteum then right against the surface of the
70:08 , what do we have living We have the osteo progenitor cells.
70:12 have the osteoblasts and we have the . So I'm laying bone down on
70:18 outside and that's what's allowing the bone grow outward, forming that circumferential
70:25 And then we said, the oo sorry, the in ostium is made
70:29 of bone or these cells that are kind of wandering around. So what
70:33 they doing? They're laying down bone the inside, creating that barrier.
70:38 then if each of these things are , you'd expect there to be spaces
70:43 hole in between them, right? I get a series of round structures
70:48 put them together a series holes, expect there to be space in between
70:53 of them, right? Well, don't have that. And the reason
70:56 , is again, you're gonna, when you build osteon, you're gonna
71:01 to use circumferential lamel to kind of out the outer space. But what
71:05 also do is you fill that interstitial with um osteoid as well, which
71:11 interstitial Lali. And then if I down an osteon, um what I'm
71:18 do is I'm gonna break it down I'm going to rebuild another one in
71:21 place. And so some of Interstitial is left over a from when
71:25 broke things down. So it's hard I'm always building up the bones.
71:31 always building and breaking down and that's we see here. So, on
71:38 outside, circumferential, on the circumferential, internal and external between the
71:47 . Interstitial when they are here. in between. So far. So
71:54 . Ok. Yeah. Yeah. osteogenic is more of a uh So
72:02 question was, is osteopro and osteogenic same word? Does it mean the
72:07 thing? So osteogenic, generally refers to the class of all
72:12 So osteo when you ever, you progenitor, it is literally meaning stem
72:16 . So osteopro is, is stem cell. So osteogenic is cells
72:21 make bone, right? How are doing? Falling asleep? Yeah.
72:31 of kind of. Yeah, Yeah, I see. Now see
72:36 that causes a smile. Y you I'm falling asleep out there?
72:41 I, I would have been asleep 30 minutes ago. Yeah.
72:46 I'm in grad school. So my and I we met in grad
72:48 We took a couple classes together and was one of two classes where they
72:54 turned off all the lights and then uh slide three minutes. I'd fall
72:59 . I was just, and then get kind of borrow your notes.
73:03 we were dating. We weren't So she had no obligation at that
73:06 to give me that for me and always got the higher grade. So
73:11 don't. Yeah. Yeah, I tease her about that. Like I
73:20 , I was a student. She . All right. When we look
73:24 spongy bone, it's, they're not there, what we're forming are,
73:29 are called trabecule. And so you kind of see here, here's the
73:33 , they're built along stress lines, ? So the idea here is,
73:38 the bone is kind of bending in direction. So what we need to
73:41 is we need to create this, uh network of, of o osteoid
73:46 in along this, along this Oh Wait, we found another stress
73:49 . We're going to build another And so basically, this is why
73:51 get this spongy looking pattern, this that you're kind of seeing here.
73:57 if you were to take a slice a TBILI, does it look much
74:00 than an osteon? What do you ? No, I mean, there
74:04 no central canal. We don't need canals because there's not a lot of
74:08 between the outside and the inside. what you'd have is you might have
74:14 you can see here, it's, an osteocyte stuck in the network,
74:17 there's another osteocyte. And what we've here is we've just cells in them
74:23 , and basically created something that has and strength. All right. So
74:28 have canicule that open up to the . You can see out here here
74:32 the osteoblast blast. Um You can here, osteoclast are gonna break things
74:38 . All right. So there's no vessels, no central canal, the
74:43 can open up to the surface so nutrients can be delivered to the cells
74:47 . Uh because these things are not large. So I think with regard
74:57 the stuff that we've talked about, , bone formation is probably the most
75:03 , right? Um You're sitting you, you can see me
75:10 Do I wanna start this right You're like, no, I don't
75:13 to do this right now. That's . Um We're gonna go ahead and
75:16 here. Let me go. Look , here's the thing about bones,
75:20 are pretty straightforward. It's just like gonna go through and name things and
75:23 probably identify certain uh points of interest then we deal with articulations. Uh
75:30 homework will include you standing in front the mirror doing silly dances like,
75:36 am I doing? Yeah. it's just movement because the best learn
75:41 is movement. All right, you dance, you can do whatever you
75:46 to do. Whatever's gonna help because gonna build your own cheat sheet,
75:51 ? So like on an exam, you're doing this, what's this
75:55 You can do that in an So you're cheating, right?
76:00 all right over
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